Overheating Mystery

[Tomm1468]

Just to clarify; so did you just swap the original fan back in?

So, when I bought the truck it was not running, and the fan was actually destroyed. that's why I bought a new one. so no I didn't put the original back in, but I had to request a specifically 4.0 fan since the 3.0 fan is apparently set backward.

 

[RonD]

Yes, water pumps on the 4.0l and 3.0l rotate in opposite directions, so fans would be different

General rule of thumb is if water pump pulley is smooth, no ribs for a belt, it turns counter-clockwise, opposite direction of the crank pulley/engine
If it has ribs then it turns clockwise, same direction as the crank pulley

4.0l has smooth pulley
3.0l has ribbed pulley
so they spin in opposite directions

Comes in handy for fan clutch nut as well
Smooth pulley means it a regular thread, right handed
Ribbed pulley means reverse thread, left handed